1. Field of the Invention
The invention relates to a method for the production of fire protection glazing, including at least two flat substrates and one transparent fire protection layer, whereby the fire protection layer includes at least one film or film system having at least one intumescent layer, and the fire protection layer is introduced between the substrates.
2. Related Technology
In order to produce fire protection glazing, it is a known procedure to employ intumescent materials that, within a glazing unit having at least two glass panes, form a transparent interlayer that expands in case of fire. When the layer expands, a considerable amount of energy of the occurring heat is absorbed by the water contained in the layer, which causes the water to evaporate. After the evaporation of the water, a foam-like heat shield is formed which, during the further course of the fire, assumes the function of heat insulation for the glass pane that lies behind the fire protection layer as well as for a room that is to be protected.
It is a known procedure to use hydrogels to form such fire protection layers. The main constituent of these hydrogel layers is usually water with admixtures of salts and stabilizing polymers. Here, the stabilizing polymers serve as gel formers. Such a fire protection layer consisting of a hydrogel is described, for example, in DE 35 30 968.
With the known methods for the production of intumescent layers for fire protection glazing, the material is applied into the glazing preferably by means of pouring, or by gel and by resin-casting methods in which the appropriate material is applied between two panes that are held apart from each other.
In the case of pouring methods, the intumescent material is poured onto a pane, after which the second pane is applied over it. Such a method is described, for example, in DE 44 35 843. Here, a drainage protection rim made of putty is placed onto a horizontally positioned glass pane, and then a fire protection solution is poured onto the glass pane. The water of the solution is removed by means of drying processes so that the layer solidifies to form a solid fire protection layer.
Conventional pouring methods, however, have a number of drawbacks. For example, time-consuming adjustment of the glass panes is necessary in order to avoid large thickness and moisture gradients over the pane. This is a serious problem especially in the case of large panes since, generally speaking, it is very difficult to handle such glass panes. Moreover, when the applied materials are drying, non-homogeneous drying conditions occur that lead to considerable quality problems and poor fire behavior due to non-homogeneities in the chemical composition and in the resultant physical properties in the x, y and z-directions. Furthermore, the dryers used define the dimensions of the panes that can be treated so that only a very limited choice of pane sizes is possible. There are likewise limits as to how the composition of the functional material can be varied since the drying process is very sensitive. Moreover, the drying process itself is very time-consuming and difficult to regulate.
The intumescent fire protection material can also be poured into an already joined double glass pane in which two panes are preferably positioned at a certain distance from each other by means of a frame-like holder. The space thus formed is then filled with the appropriate material. This is described, for example, in DE 195 25 263.
The known gel and casting-resin methods have various drawbacks. For example, only production in the final dimensions is possible since the pouring procedure can only be used with prefabricated double glazing having certain dimensions. The constructions are often very thick and heavyweight. In the case of thin layers, problems also arise in connection with the thickness tolerance over the larger dimensions. Due to the flowability of the gel, bulges are formed or even delamination between the gel and the pane can occur. A large problem is also posed by the edge sealing that is necessary to delimit the area of the gel that has been poured in.
Therefore, there is a need for a method for the production of fire protection layers with which the above-mentioned disadvantages do not occur. A major improvement is the approach of producing the fire protection layers separate from the glazing unit into which they are to be installed at a later point in time. DE 28 15 900, for example, discloses a method for the production of a solid layer of an intumescent material comprising hydrous or hydrated metal salts in which the fluid material is poured into a mold where it hardens.
DE 27 52 543 describes a method for the production of a light-permeable, fire-retardant glass pane with at least one solid layer made of hydrated sodium silicate, whereby the layer is sandwiched between two glass panes. The intumescent layer can be formed, for example, on the glass pane; it can be provided as a film on its own, or else it can consist of several layers.
DE 35 09 249 discloses a method for the production of a transparent fire protection sheet. With this method, an aqueous solution of an expandable material is applied onto a support, this layer is dried by applying heat until the residual water content ranges from 20% to 48% by weight and the expandable material thus obtained is applied as at least one layer onto at least one glazing pane.
Likewise known are fire protection means in the form of hybrid film systems in which at least one film is coated with intumescent material. Such film systems can be produced, for example, by means of a continuous, cascading process in which additional films or film layers are applied onto a base film.
Such film systems typically have at least one layer having a high elasticity so that the layer system exhibits advantageous mechanical properties and can be transported, stored and processed very well. In order to simplify the introduction into various environments, the film system can have at least one adhesive layer with which it can be introduced into various components of a glazing unit and can be affixed to the components.
Therefore, prefabricated fire protection films or film systems entail several advantages in comparison to conventional fire protection means. A major advantage lies, for example, in the flexible choice of the size of the fire protection glazing units that are to be produced, since the films employed can be cut into any desired size and can be processed in this form. In order to be able to realize correspondingly large glazing units, however, the introduction of the fire protection films into a glazing unit calls for methods that are adapted to the new circumstances.
In the realm of the production of laminated safety glass, it is likewise a known proce-dure to introduce functional films into glazing units. On this subject, for example, DE 36 15 225 A1 and DE 100 02 277 A1 describe special methods. However, the prior-art methods are not suitable for effectively introducing fire protection films into a glazing unit, since specific requirements have to be made of safety glass and these differ from those for fire protection glazing.